Looking at the evidence, I fail to see what the problem is
[In reply to]

Can't Post

It's saying here in your example that spirits are inhabiting bodies. From the evidence, the original person is dead. From the evidence (take the Nazgul for example) the body changes into something that is not human and more related to death and decay.

How is this in any practical sense different from a zombie?

Most zombie movies I've seen don't really go into the HOW but the results are the same. The original person is gone. The body changes into something more related to death and decay. Supernatural animation is involved.

Do we see any examples of a whole person, completely natural and life-like in appearance, who has been possessed by Sauron or another spirit? Not that I'm aware of. The barrow-wights, the Nazgul, are not critters that will pass for living beings as they stroll through town.

Middle Earth is a dark place. A good chunk of its inhabitants are Elves who have been horribly mutated by Sauron's old boss Melkor (Morgoth). Mountains are hostile sometimes. Trees try to eat you. Men are cursed so they cannot be released even in death. Werewolves and vampires exist (Sauron takes on the form of both).

To each their own, but I don't find zombie-anything a stretch. King Arthur: Who are you who can summon fire without flint or tinder?